The present invention is directed to a grinder which can grind a large range of volumes of substance to be ground. More particularly, the present invention is directed to a grinder for use in grinding substances such as whole bean coffee.
A variety of grinding devices or grinders have been provided by the prior art. In particular, the Assignee of the present invention notes three patents which show grinding devices: U.S. Pat. Nos. 5,042,731 issued Aug. 27, 1991 to Ford; 4,813,622 issued Mar. 21, 1989 to Nidiffer et al.; and 4,714,206 issued Dec. 22, 1987 to Nidiffer et al. All three of these patents show grinding devices which are designed to grind beverage brewing substances such as whole bean coffee for producing a brewed beverage therefrom.
The Ford '731 patent and the Nidiffer et al. '622 patent show grinders which include a discharge chute or discharge chute assembly which prevents a separation of chaff from the ground coffee. Many types of coffee beans have a thin membrane which dries during the roasting process. Upon grinding of the coffee beans, the thin membrane is separated from the rest of the coffee bean creating a light bean debris which separates during grinding. The dried, ground membrane is commonly called chaff. Chaff does not detract from the flavor of coffee, however, due to its light weight, it is prone to being separated from the ground coffee discharged from the grinder to a container waiting therebelow. Free-floating chaff can create problems within the grinder and therefore it is desirable to retain the chaff within the bulk of the ground coffee. Further, it is desirable to retain chaff in the coffee in order to help reduce caking problems which typically occurs in ground coffee especially oiler, dark roasted coffee bean as such as ground coffee is discharged from the grinder. Both devices as shown in Ford '731 and Nidiffer '206 show such chaff retaining structures.
One of the problems encountered with retaining chaff in the ground substance dispensed from the grinder is that the mechanisms to retain chaff often results in ground coffee or build-up within the grinder. One of the mechanisms for retaining chaff in the ground coffee is to provide a back pressure on the grinder to prevent the free-flow of ground coffee from the grinder which results in air separation of the chaff from the ground coffee. If the ground coffee were free to flow from the grinder, the chaff being a lighter substance, would tend to separate as the ground coffee is dispensed into the collection container. As such, structures are provided which prevent the "blowing" of ground coffee from the grinder. As the coffee is dispensed from the grinder, it tends to flow into the bag thereby preventing the separation of the chaff from the ground coffee. However, these back pressure creating structures tend to result in accumulation of chaff thereon or on the discharge assembly structure. As such, it is desirable to provide mechanisms to remove the ground coffee and chaff from these structures.
As might be expected, when a finite volume of whole bean coffee is ground, it tends to be fluffed or expanded during the grinding process. As such, when the ground coffee is dispensed into a waiting container such as a bag, the finite volume which previously fit into the bag will likely overflow the bag as a result of the fluffing or lofting created during the grinding process. Part of the reasons for the lofting is the retention of the chaff within the ground coffee. However, it is desirable to retain the chaff in the ground coffee for the reasons noted hereinabove.
Heretofore, prior art devices have not solved the problem of fluffing. As such, users of prior art devices have been required to manually shake or tap the ground contents into the container or bag in order to prevent overflowing. This problem is also seen in coffee stores which sell whole bean coffee for grinding on the premises. The salespeople must wait for coffee to be ground and tap or shake the bag in order to prevent overflowing. As might be expected, this waiting reduces the customer service rate and incrementally increases the labor time associated with the grinding of whole bean coffee.
To further facilitate the automatic settling of coffee, it would be desirable to place a bag near or on the grinder and allow the operator to leave the bag during the grinding process. As such, a bag retaining device would be desirable for use with a grinding process which automatically settles the ground coffee. A bag retainer as shown in U.S. Pat. No. 2,290,747 issued Jul. 21, 1942 to Henry. The bag holder device as shown in Henry is complicated and as such it would be desirable to provide a simplified bag holding structure.
Another problem encountered with coffee grinders is that it is desirable to prevent grinding prior to the proper placement of a bag near the dispensing chute. U.S. Pat. Nos. 5,220,998 issued Jun. 22, 1993 to Ford; 4,714,206 issued Dec. 22, 1987 to Nidiffer et al.; and 4,685,624 issued Aug. 11, 1987 to Nidiffer show switches which are generally activated by the placement of a bag beneath a dispensing or discharge chute assembly. While these devices assure that a bag must be somehow placed relative to the discharge chute assembly, they do not retain the bag in position against or for dispensing from the discharge chute assembly.
Other problems which occur with prior art devices is that particles of metallic material may be accidentally deposited in the grinder hopper and subsequently ground into the ground coffee discharged therefrom. While coffee is placed into a filter, generally either paper or metal mesh, and thus kept separate from the actual beverage liquid produced during the brewing process, introduction of metal into the ground coffee may produce undesirable flavor. Additionally, it is always preferable to prevent undesirable substances from being mixed into foodstuffs. The prior art, heretofore known, has no means for extracting such metallic materials. As such, it would be desirable to extract such metallic materials from whole bean coffee prior to grinding.
Finally, an additional problem which occurs with prior art grinders is that they generally handle only a small range of volumes. As such, such grinders may overheat and cease to operate if a substantial grinding burden is placed on them. As such, it would be desirable to provide a way of cooling the grinder to permit grinding of larger volumes and a greater range of volumes of whole bean coffee without overheating the grinding device.